When a client hires an architect to design a project, the architectural firm is legally responsible for all of that work, even though they hire various consultants to help them with different aspects of the design. The consultants, in turn, are liable to the architect, not the client. They have “privity of contract” with the architect. The architect also has privity of contract with the client. The consultant has no real legal relationship with the client and generally all communications between the consultant and the client go through the architect.
While the architect may spend many months negotiating a contract with the client, it is amazing how little time goes into the contracts with the consultants. Rather than drafting a contract with the consultant, architects often just ask the consultant for the consultant’s standard letter of agreement, attach a description of the work and sign. It is not very different from contractors who tell their subs to “Start on Monday” without having any paperwork. This can result in problems, since the architect’s responsibilities trickle down to the consultants, who do not necessarily have the same level of legal liability as the architect. The problems usually involve invoices for the work. I have seen invoices from consultants for a large number of hours times various hourly rates, with no explanation of what work was done and when.